Preparation method of fiber

ABSTRACT

A preparation method of a fiber is provided. In the preparation method of the fiber, a polymer is dissolved in a mixing solution of an ionic liquid and a salt to form a spinning viscose, wherein the salt includes KCl, KBr, KOAc, NaBr, ZnCl 2  or a combination thereof. Afterwards, the spinning viscose is used as a material to perform a spinning process so as to form a fiber.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of and claims the priority benefit of U.S. application Ser. No. 14/740,279, filed on Jun. 16, 2015, now pending, which claims the priority benefit of Taiwan application serial no. 103142137, filed on Dec. 4, 2014. The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to a preparation method of a fiber, and more particularly relates to a preparation method of a regenerated fiber.

2. Description of Related Art

In recent years, scientists actively work in manufacturing regenerated fibers by dissolving existing polymer materials so as to replace the consumption of natural fibers. The regenerated fiber can be widely applied in a variety of industries, such as home textile, thin film, flexible electronic display, cosmetics, medical drugs and food additive.

In the process of manufacturing regenerated fiber, it is usually required to dissolve polymer in the solvent. For example, N-methylmorpholine N-oxide (NMMO) is usually used as the solvent for current commercial wet spinning of cellulose fibers. However, the process temperature of NMMO is higher (110° C.-130° C.), which causes the solute degradation and energy consumption. Besides, because NMMO is a strong oxidizing agent, it is required to add stabilizing agent in the process additionally, so the recycling cost is higher. Therefore, increasing fiber strength effectively, lowering process temperature and energy conservation are topics to be actively studied currently.

SUMMARY OF THE INVENTION

The invention provides a preparation method of a fiber, and the preparation method of the fiber increases polymer solubility, enhances fiber strength and lowers process temperature.

The invention provides a preparation method of a fiber as follow. First, a polymer is dissolved in a mixing solution including an ionic liquid and a salt to form a spinning viscose, wherein the salt includes KCl, KBr, KOAc, NaBr, ZnCl₂ or a combination thereof. Afterwards, the spinning viscose is used as a material to perform a spinning process so as to form a fiber.

In an embodiment of the invention, the ionic liquid is composed of a cation and an anion, and the cation is alkyl imidazole type including a structure illustrated in Formula 1:

wherein R₁ and R₂ are respectively a alkyl group having 1 to 4 carbon atoms, and the anion is Cl⁻, Br⁻ or CH₃COO⁻.

In an embodiment of the invention, the ionic liquid is 1-ethyl-3-methylimidazolium acetate.

In an embodiment of the invention, the polymer includes cellulose or poly-metaphenylene isophthalamide.

In an embodiment of the invention, a weight ratio of the salt and the ionic liquid is 10:90 to 0.1:99.9.

In an embodiment of the invention, the polymer is 5 wt % to 20 wt % by weight based on a total weight of the spinning viscose.

In an embodiment of the invention, the polymer is dissolved in the mixing solution at a temperature of 60° C. to 80° C.

In an embodiment of the invention, the spinning process is a wet spinning method or a dry-jet wet spinning method.

The invention provides a preparation method of a fiber, and the preparation method of the fiber enhances fiber strength and lowers process temperature, so the energy consumption of the process is improved and the recycling cost is lowered. Besides, the invention provides a spinning viscose with good spinnability, and fibers with higher strength can be obtained through wet spinning method or dry-jet wet spinning method.

The concepts and advantages of the present invention will become more apparent in view of the following embodiments and accompanying detailed information.

DESCRIPTION OF THE EMBODIMENTS

According to an embodiment of the invention, a preparation method of a fiber is provided. First, a polymer is dissolved in a mixing solution including an ionic liquid and a salt to form a spinning viscose. In the present embodiment, the polymer is cellulose or poly-metaphenylene isophthalamide, for example. The salt is KCl, KBr, KOAc, NaBr, ZnCl₂ or a combination thereof, for example. The ionic liquid is composed of a cation and an anion, and the cation is alkyl imidazole type including a structure illustrated in Formula 1:

wherein R₁ and R₂ are respectively a alkyl group having 1 to 4 carbon atoms, and the anion is Cl⁻, Br⁻ or CH₃COO⁻, for example. In another embodiment, the ionic liquid is 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc), for example.

In the present embodiment, the salt is added into the ionic liquid. A weight ratio of the salt and the ionic liquid is 10:90 to 0.1:99.9, preferably 3:97 to 1:99, and more preferably 3:97, for example. After adding the salt into the ionic liquid, a polarity of the ionic liquid is increased, so as to increase polymer solubility.

In the present embodiment, the polymer is 5 wt % to 20 wt % by weight based on a total weight of the spinning viscose, for example. In another embodiment, the polymer is 10 wt % to 15 wt % by weight based on the total weight of the spinning viscose, for example. In yet another embodiment, the polymer is 10 wt % by weight based on the total weight of the spinning viscose, for example.

It is worth mentioning that, the polymer is dissolved in the mixing solution of the ionic liquid and the salt at a temperature of 60° C. to 80° C. The process temperature of using NMMO in the prior art is 110° C. to 130° C., which consumes more energy. In comparison, using the ionic liquid of the invention lowers the overall process temperature effectively, so polymer degradation is improved with energy conservation effects. Besides, the ionic liquid also has advantages including no volatility and high chemical stability.

Afterwards, a spinning process is performed by using the aforementioned spinning viscose as a material to form a fiber. In the present embodiment, the spinning process spins the spinning viscose through a dry-jet wet spinning method, for example, and the spinning dope enters into coagulation bath (such as ethanol, water or a combination thereof) and then washed in water, then the fiber preparation is completed. In other embodiments, a wet spinning method can also be used to perform the spinning process.

Experimental examples will be used to explain the fiber preparation of the aforementioned embodiments and characteristics thereof in detail. However, the following Experimental examples are not intended to limit the invention.

Experimental Example

To prove the excellent fiber strength of the fiber prepared by the fiber preparation method of the invention, and the overall process temperature is lower with energy conservation effects, the following Experimental Examples are performed.

Fiber Preparation Example 1

48.5 g ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) and 1.5 g (3 wt %) KOAc are mixed and dissolved at 60° C. to form a mixing solution. Afterwards, 5 g cellulose is added, and mixed and dissolved at 60° C. to form a spinning viscose. The spinning viscose is used as a material to perform a spinning process, and a cellulose fiber is formed through a dry-jet wet spinning method.

Example 2

48.5 g ionic liquid [EMIM]OAc and 1 g (2 wt %) KOAc and 0.5 g (1 wt %) KBr are mixed and dissolved at 60° C. to form a mixing solution. Afterwards, 5 g cellulose is added, and mixed and dissolved at 60° C. to form a spinning viscose. The spinning viscose is used as a material to perform a spinning process, and a cellulose fiber is formed through a dry-jet wet spinning method.

Example 3

48.5 g ionic liquid [EMIM]OAc and 1.5 g (3 wt %) KBr are mixed and dissolved at 60° C. to form a mixing solution. Afterwards, 5 g cellulose is added, and mixed and dissolved at 60° C. to form a spinning viscose. The spinning viscose is used as a material to perform a spinning process, and a cellulose fiber is formed through a dry-jet wet spinning method.

Example 4

48.25 g ionic liquid [EMIM]OAc and 1.75 g (3.5 wt %) KBr are mixed and dissolved at 60° C. to form a mixing solution. Afterwards, 5 g cellulose is added, and mixed and dissolved at 60° C. to form a spinning viscose. The spinning viscose is used as a material to perform a spinning process, and a cellulose fiber is formed through a dry-jet wet spinning method.

Example 5

48.5 g ionic liquid [EMIM]OAc and 1.5 g (3 wt %) KCl are mixed and dissolved at 80° C. to form a mixing solution. Afterwards, 5 g cellulose is added, and mixed and dissolved at 80° C. to form a spinning viscose. The spinning viscose is used as a material to perform a spinning process, and a cellulose fiber is formed through a dry-jet wet spinning method.

Example 6

48.5 g ionic liquid [EMIM]OAc and 1.5 g (3 wt %) KBr are mixed and dissolved at 80° C. to form a mixing solution. Afterwards, 10 g poly-metaphenylene isophthalamide is added, and mixed and dissolved at 80° C. to form a spinning viscose.

Comparative Example

5 g cellulose is added into 50 g ionic liquid [EMIM]OAc, and mixed and dissolved at 60° C. Afterwards, a spinning process is performed, and a fiber is formed through a dry-jet wet spinning method.

Measurement of Fiber Strength

Afterwards, as for the cellulose fibers of Example 1 to Example 5 and the cellulose fiber of Comparative Example, the measurement of fiber strength are performed by ASTM D3822 measurement method, and the measurement results are shown in the following Table 1.

TABLE 1 Salt and Fiber strength Ionic liquid concentration (gf/den) Example 1 [EMIM]OAc 3 wt % KOAc 4.6 Example 2 [EMIM]OAc 2 wt % KOAc/ 3.8 1 wt % KBr Example 3 [EMIM]OAc 3 wt % KBr 4.1 Example 4 [EMIM]OAc 3.5 wt % KBr 4.9 Example 5 [EMIM]OAc 3 wt % KCl 3.5 Comparative [EMIM]OAc 0 3.2 Example

As shown in Table 1, Comparative Example uses only ionic liquid to dissolve the cellulose, and the fiber strength of the cellulose fiber is 3.2 gf/den. In comparison, Example 1 to Example 5 perform cellulose fiber preparations according to the preparation method of fiber provided by the invention, wherein the ionic liquid is [EMIM]OAc, and the salts including 3 wt % KOAc, 2 wt % KOAc/1 wt % KBr, 3 wt % KBr, 3.5 wt % KBr or 3 wt % KCl is added into the ionic liquid respectively. Afterwards, the cellulose is dissolved in a mixing solution of the ionic liquid and the salt, and the fiber is formed through a dry-jet wet spinning method. As shown in Table 1, the fiber strengths of the cellulose fibers formed in Example 1 to Example 5 are 4.6 gf/den, 3.8 gf/den, 4.1 gf/den, 4.9 gf/den and 3.5 gf/den, respectively. Therefore, compared to the cellulose fiber prepared by Comparative Example, the fiber strengths of the fibers prepared in Example 1 to Example 5 are obviously higher. In other words, fiber strength is obviously improved through the preparation method of fiber provided by the invention.

To sum up, the preparation method of fibers provided by the invention increases fiber solubility and strength. The ionic liquid has high chemical stability and high heat stability, but with no volatility, and the ionic liquid can be recycled and reused. After adding the salt into the ionic liquid, the polarity is enhanced, the polymer solubility is improved, and the fiber strength is effectively increased. Besides, the process temperature is also lowered to improve the energy consumption of the process. In addition, compared to the prior art using NMMO, the preparation method of fiber provided by the invention does not require additional stabilizing agent or DMSO, so the recycling cost is reduced with industrial values. The invention also provides a spinning viscose with good spinnability, and fibers with higher strength can be obtained through wet spinning method or dry-jet wet spinning method.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents. 

What is claimed is:
 1. A preparation method of a fiber, comprising: dissolving a polymer in a mixing solution including an ionic liquid and a salt to form a spinning viscose, wherein the polymer comprises cellulose or poly-metaphenylene isophthalamide, the salt includes KCl, KBr, KOAc, NaBr, ZnCl₂ or a combination thereof, and a weight ratio of the salt and the ionic liquid is 10:90 to 0.1:99.9; and performing a spinning process using the spinning viscose as a material to form a fiber.
 2. The method of claim 1, wherein the ionic liquid is composed of a cation and an anion, and the cation is alkyl imidazole type and the cation includes a structure of Formula 1:

wherein R₁ and R₂ are respectively a alkyl group having 1 to 4 carbon atoms; the anion is Cl⁻, Br or CH₃COO⁻.
 3. The method of claim 1, wherein the ionic liquid comprises 1-ethyl-3-methylimidazolium acetate.
 4. The method of claim 1, wherein the polymer is 5 wt % to 20 wt % by weight based on a total weight of the spinning viscose.
 5. The method of claim 1, wherein the polymer is dissolved in the mixing solution at a temperature of 60° C. to 80° C.
 6. The method of claim 1, wherein the spinning process is a wet spinning method or a dry-jet wet spinning method. 